Sound propagation techniques determine how sound waves travel in a space and interact with the environment. In many applications, it is important to be able to simulate sound propagation in large scenes, such as games and training in both indoor and outdoor scenes, noise prediction in urban areas, and architectural acoustics design for buildings and interior spaces such as concert halls. Realistic acoustic effects can also improve the realism of a virtual environment. Acoustic phenomena such as interference, diffraction, and scattering for general scenes can only be captured by accurately solving the acoustic wave equation. The large spatial and frequency domain and accuracy requirement pose a significant challenge for acoustic techniques to be used in these diverse domains with different requirements.
Sound sources can be omnidirectional (e.g., radiating sound isotropically) or directional (e.g., radiating sound anisotropically). Most sound sources we come across in real life (e.g., ranging from human voices through speaker systems in televisions, radio, smartphones, machine noises in cars, aircrafts, helicopters, and musical instruments) are directional sources that have a specific directivity pattern. This directivity depends on the shape, size, and material properties of the sound source, as well as a complex interaction of the processes of vibration and sound radiation, resulting in varying directivity at different frequencies. Due to the non-uniform radiation of sound, directional sources have a significant impact on sound propagation and the corresponding acoustic response of the environments. Acoustic effects generated from directional sources are noticeable in everyday life: a person talking towards/away from a listener, positioning of different types of musical instruments in an orchestra, good-sounding places (sweet spots) in front of television in the living room, aircraft, helicopter, or fire trucks in an urban environment.
Analogous to source directivities, listeners also have directivities. In other words, listeners do not receive sound in the same way from all directions. The human auditory system obtains significant directional cues from the subtle differences in sound received by each ear which are caused by the scattering of sound around the head. Listener directivity can be used to enhance a user's immersion in a virtual environment by providing the listener with cues corresponding to the directions the sound is coming from, and thereby enriching the experience.
Various techniques may be used in predicting or modeling sound propagation. Some techniques may involve assuming sound travels like rays (e.g., beams of lights). Other techniques may involve assuming sound travels like waves. However, current techniques are unable to efficiently support source or listener directivity in an interactive wave-based sound propagation model.
Accordingly, there exists a need for methods, systems, and computer readable media for supporting source or listener directivity in an interactive wave-based sound propagation model.